Field of the Invention
This invention relates to metallic fencing and railing systems and in particular to improved designs for manufacturability, adjustability, and strength.
Background Art
Metal fences and railings are costly to fabricate and are subject to environmental degradation, particularly rusting when steel is used. In its most simple form, a fence panel comprises a pair of horizontal metal rails (top and bottom) that are connected to the top and bottom portions of a number of vertical metal pickets - the top rail is connected to the top portions of the pickets and the bottom rail is connected to the bottom portions of the pickets—whereby a single unit is formed. The rails and pickets are joined together at a manufacturing shop, typically by welding, and then transported to a customer's site to accommodate a range of different conditions including horizontal and sloped surfaces. The term “panel” as used herein denotes this simple structure, irrespective of whether the pickets all intersect the rails at 90°—such as when the panel is used on a horizontal surface, or whether the pickets all intersect the rails at an angle θ, which is other than 90°—such as when the panel is used on a sloped terrain or as a railing on a stairway.
For maximum strength and durability fence panels are made from metal (e.g., steel or aluminum) and then welded, which is best accomplished at the shop using equipment that is not readily transportable. This is particularly important when the panel is a railing whose pickets are all oriented at the same predetermined angle θ with respect to the rails and spaced precisely apart from each other.
Railing panels are custom-made to match the angle of a stair, ramp or sloped-terrain. This is achieved by taking measurements at a customer's site to determine the angle and length of each railing panel. The measurements are then taken back to the shop and pickets are cut at the measured angle and welded to the top and bottom rails of the railing. Thereafter, the finished railing is taken to the customer's site with the hope that the angle was measured, cut and welded correctly. Three operations were therefore needed to construct the railing:
1) Field measuring;
2) Cutting pickets at the exact angle; and
3) Welding the pickets to the top and bottom rails at that exact angle.
If there was a mistake in any of the above operations, the railing will not look level or symmetrical and will have to be scrapped and/or re-fabricated. To avoid such a waste of time and material, many solutions have been proposed that enable pickets to be oriented at an adjustable angle with respect to the top and bottom rails. Those solutions have frequently required that holes be drilled into the pickets, thereby exposing them to rust, particularly when the pickets comprise steel tubes. Other solutions have employed brackets, and numerous extra parts to achieve pivotal connections between the pickets and the rails —all of which are undesirably expensive. It is therefore desirable to design an environmentally durable metal fence panel that is easy to manufacture, requires only a minimum number of component parts and, when used as a railing, can be adjusted at a customer's site to match the exact angle of the stair, ramp or sloped-terrain.